Ments



Jan. 24, 1928.

Re, 16,860 M. K. ARMSTRONG ART or' MAKING PLAsTER BOARD Original Filed March l5, 1919 3 Sheets-Sheet l y ,W a# 2% Z? fw,

Jan@ 24, 192s.

M. K. ARMSTRONG ART 0F....MAKING PLAs'rER BOARD 3 Sheets-Sheet 2 Original Filed March 15, 1919 OZyQHMW/Jqiy NVvjy ART l0F MAKING PLASTER BOARD I 3 Sheets-Sheet 5 original Filed Marci; 15, 1919 www im. www mi Reissue'd Jan. 24, 1928.

yUNITED STATES PATENT OFFICE.

MORGAN K. ARMSTRONG, OF HAMPTON, VIRGINIA, ASSIGNOB, BY MESNE ASSIGN- MENTS, TO UNITED STATES GYIJSUM COMBANY. i

ART OF MAKING PLASTER BOARD.

Original No. 1,348,387, datec'tAiigust 3, 192i), Serial No. 282,837, filed- Mareh 15., 1919. Application for reissue filed June 3, 1922. Serial No. 565,737.

rl.`his invention relates to the improvements in the art oit making plaster board and addressed to a novel process in the manufacture of such board. The invention e further consists of the matters hereinafter it" board shown in the drawing -l adhere.

afterwards applying the opposite.

il l) described and more particularly pointed out in the appended claims.

The terniplaster board isused herein in its generic sense, although the illustrative s is technically -termedpal Wall board, inasmuch as it is adapted to'form the finished surface of a Wallexclusive of decoration.

The illustrativefboard consists generally of top and bottoni covering sheets of paper or otheriibrous material, preferably a Manila paper, either' fully or partially sized, andl an. intermediatelayer ,consisting of -a plaster body to" which said covering sheets Heretofore one type of plaster board has been made byiolding the-margins ci one cover sheet aroundthe edges ot and upon the opposite face' of the plaster ,body and y y cover sheet, the-margins ofwhich OYerliethe folded margins. This method occasionally pro-r duced plaster board having edges reduced instrength.-

'l Amongother objects, tliie invention is' i-ntended to provide a 'novel 'and improved method' .of making plaster board 'having i stronger edgesand 'reinforced siibstantially` i employing one giti'idinal' section throughoutits Width' by the' adhesion oi the Cover'sheets tothe pla-sterbody or core, The character of the invention may be best u y derstood by reference to an apparatus' illustrative process embodyrv ing the principlesof vthe ini'entioni The` apparatus is illustrated in the accompanying drawings, in which :v "lTigQ 1 represents diagrammatioa-lly a lo`n- .th-relish th'arreatu's; Fig. 2. represents a top plan View of :the apparatus; 'r t 5 ,Fig. 3'represei its,.onl an enlarged scale, a

section .throng Figif2,in' plane indicated parte Fig.4 4 .represents @partial sectional lView a plane indicated' jby"' the lifne 4- 4 of Fifi-lai" A" Figi' 5' represents,-on afstilll larger 'sea-le, a

` 'ftrans erse-sect paratus, in a plane .indicated by the line -'of Fig. 2; l

`Fig. 6 represents a. transverse section, in a plane indicated by the line @-6 of Fig. 2;

Figs. 7 and 8 represent, respective-ly, transverse sections through the apparatus, in planes indicated by the lines 7--7 and 8--8 of Fig. 2; i

Fig. 9 represents a top plan view of the bottom sheet edge-folding or turning horns; Fig. 1.0 represents a transverse section through the finished board; and

Fig l()a is an elevation ot the spread 'rolls illustrating the manner. of mountand-operatively connecting them.

The principle of the .improved process Will b'e readily understood the illustrative apparatus and its mode of operation in producing one `form of iinproved plaster board. This illustrative plaster board comprises a board-like body ot plaster covered on the opposite faces With cover sheets of paper or the like which adrom a description of titl here thereto'substantially-,through its Width,

thereby adhesively vreinforr'zing theA same .from edge to edgef, the edgesiof the pla-sterI bodybeing coveredby coversheet margins which arefolded over said edges and oe-l inented in plaee. The method. employed by the'illustratiye a-pparatusoi' ma ring .this type ofboard coinprises vingeneral: Placing a quantityV oi' plastic' :material jupon a' covery sheet spread ingthe plaster to a uniformv deptharul applying an opposite cover sheet;both vsheets adhering thereto substantially through.v the Width ofthe body of'plaster; ing the margins t.ora 'covern edges ofI the body of plaster and :oementing said folded margins in place. "In 'the illustre tive boardone coversheet is made suiiiciently vv'ideto' permit the margins thereoi to 'be folded around the edges' of the' plaster body andupon the opposite tace of thegboard.

In the; present instance, thev sheet. or .strip of'paper which is made Wide'enough to cover' the edges .of the board is illustrated andre-l f'erred tohereinl asthe bottoni: sheet.A lThe opposite sheet is referred to as the top sheet, although' it will be ohvionsthat t-h'e-arrangefv ment of the ,cover sheets may, if desired, he. reverseflf v- 1 letti1/'drawingsthe bottoiand 'ep' sheets.

sheet over Athe i'asoo the board approaches the common axial pla-ne ot the spreading rolls, it lcomprises a bottoni sheet, having marginal 'parts on which there is no plastic material extending beyond a plastic body on said sheet, a lasterl body and a top sheet applied thereto, aving its edges projecting slightly beyond the same. Since the plates do .not project into the common diametric plane of lthe spreading rolls, Where the distance between the rolls is least, but terminates short of said plane, a little ot` the plastic mixturewill be spread out (as the board passes beyond the ends of the mold boards) over the marginal parts ot' the bottom sheet (as shown in Fig. 5), the escaping plaster being indicated by the numeral and the main body et the plaster being indicated by the numeral 31. By having the top roll 16 somewhat shorter than the width et the top sheet, the plastic mix is prevented from collecting on the ends of said roll and hardening thereon. Y

After the board passes the spreading rolls, the marginal parts of the bottom Esheet prevented from moving ployed, it is desiral'ile to provide means .tor treating the margins ot vthe paper, so that they may be more easily iolded and will more readily remain i'n folded position, and not tend to unfold. In the illustrative apparatus, means are provided tor -soitening the marginal parts ot the bottom sheet before such margins pass the folding horns. Such means comprise steam pipes 40 placed near the rear end o't' the platform 18 in such a position that they are adapted to discharge jets ot steam on the marginal edges ot the sheet in order to soften them.

To prevent buckling or bending iuinvard oit the plaster-'board or of the top sheet, during the action ot the 'folding horns, an antibuckling plate 41, which is narrower than the top sheet 12, is placed to bear on the top of the plaster board, said plate simply resting by its', weight on the top sheet and being. forwardly with the advancing plaster board by means ot a bar 42 which extends outwardly beyond the plat- Jform 33 and is engaged against the upright posts13.

Asthe plaster board passes beyond the folding horns, there is aptv to be a slight excess of plaster at the edges of the turnedover marginal parts of the bottom sheet (see Fig. .7 To remove this plaster and to smooth down any that remains in this position, I provide narrow rolls 44, one for each margin of the board. Said rolls vare mounted on a shaft 45 to the end et which is at tached a pulley 46. Thispulley is connect ed up to drive the rolls 44 in a direction opposite to theadvance of the board, so that they will in eil'ect act as brushes to remove the excess plaster and to throw it rearwardly on trays or catch plates 47 located at the (which will hereinafter be` referred lto by lthe numeral32), with the" small amount of plaster spread out thereon, are turned over to cover the edge of the plaster body and upon the top sheet by means of folding horns which will now be described.

A table 33 is located forward of the roll 15n which supports the rear loop of the endless belt 15) with .its surface in supporting engagement with. the top lap ofthe belt 15. Said table is wider vtransversely than the belt, and is somewhat wider than' the bottom sheet of the plaster'board. Ateach side of said plaster board are mounted folding horns 34 of familiar construction, said horns at their rear ends being substantially pla-ster thereon acts parts 3S of the top'sheet, as clearlyshQwn of the cross section shown in Fig. 6, and at their front ends, being of thelsection shown in Fig. '7, Said horns are mounted'on`r an 'overhanging block attached'to longitudinal strips 86 fixed atfthe "sides of the table 3. VThe front end of each horn, as willbe seen, has its turned-over part 37, bent's o that itis somewhat inclined from. the outer edge of the board to andA below the horizontal, as clearly shown in Fig. 9. "As the board isdrawn forward, the marginal parts 32 of the bot-tom sheet are'eaughtby the rear ends of the horns and said parts 32 ywith the plaster 30 are bent or turned over upon the top sheet, the several successive'steps of the turning process being indicated in Figs. 5, Gand l. f

In turning over the marginal parts 32, the to depress the marginal in Fig; 7, thus leaving a substantial body 'of plaster between .the adj'aeent'jp'arts of lthe top sheet and of the turned-over margins of theibottom sheet.l

When stiff or-partially-sized'paper is om? rear of said rolls and attached, as show-nn to the bar 42. The rolls 44 are so located andare made of such a `width. with reference to the ,turned-over marginal parts ot the bottom. sheet of the plaster' bo-ard that each roll will vextend beyond its associated edgeof the board fon one side, and beyond the space occupied bythe plaster to be removed on the other side,vi.n order to take care of the usual lweaving ot the paperin the. manufacture ot the board,

After leaving the .rolls 44. the board is passed under a weighted ironing or smoothing member 48, This is in the form o't a plate .which may be attached tocables 49 passing over pulleys 50, so that it may be lifted out. of the :road when threading the machine. lSaid ironing or smoothing member is wider than the plaster board so that it extends beyond both edges of said board. It is prevented from advancing andinoving vforward with the boardby means of chains 51 which are attached to the .upright posts.

name applied to it suggests, irons out and The said vironing member, as the -smooths any Wrinkles or buckles that appear or -tend to form in the plaster board.

In the making ofthe board the sheets are preferably so proportioned that the inarginal parts 38 of the top sheet approach as nearly as may be the edges of the board, thus not only giving all the reinforcing strength to the edges of the board that may be obtained by this construction, but also insuring three thicknesses of papier adjacent nailing `the board inplace.. A

lVhile in describing the method for inaking the board, I have referred to paper as the edele of theV board tobe engaged when :i the p r-e'terred coverings for the plaster body,

it will bc understood-that the invention is not limited thereto. as sheets or strips vof any material vadaptable to the purpose may be used, and I therefore, in claimingthe "f process, refer to :the sheets inclosing. the

plastic bodyof .the board, Aas librous vmaterial.

Obviously v.the Vimproved method `may be per-formed by other means or apparatus than the illustrative appara-tus referred. to

herein and is capable of, contemplation apart from' the particular Aineansfor. Aapparatus employed for performingit. Moreover, the method is not limited tothe .pro-

f duction of the specific article herein illustrated but the principles thereof. may be .applied in making other vforms Yof plaster board or the like. `Also, it. .not indispensable that all the .stepsofvthe villustrative method be employed. conjointly many/given as to leave marginalparts vof said sheet-,ex

posed at each: side of the'same beyondfthe intended width. of the plaster boa1'1d,\ .o f'fs,uperposing a .narrower top. sheet oftibrous material on said .plastic ymit and ty the same time spreading. the plastic mim e'enl'y over the. bottom sheet to wthe .intended/ tinckness of. the board,v of turning nivel-the pro.- jecting marginal' parts :of the hottoii'i'sheet to overlap the marginal parts of the-top sheet, first spreading .on said.v prdirect-fing parts. a sxnzallamountofplasten soithav said small amount is turnedpver with the/.said projecting I nargina lg parts .ofthe .bottoni Shes-.t upon the marginal rafts-ette@ top sheet, vthev turningf-oyerprocess, being' 'ebntinued so as: to, depressi the.;l mangi al.y vparts of the top sheet,l and. o,f.ironi1i`g}eut;and smoothing they board4 to. thoroughly, adhere the *10P 'and bttalsleets te 'distesi/91. f.-

'2. The continuous process ,of making plaster board, which :consists of advancing a bottom sheet of fibrous material and softening the n ia-rginalparts thereof, of depositing a plastic mixture on` said bottom sheet to form .the .body lof the board, in such inanner as to yleave said softened marginal parts bare and exposed, of superposng a narrower top sheet of fibrous material on said plastic mixture. and at the saine time spreading, the l ijnixture. evenly :over :the bottom sheet to the .desired thickness, of applying ,a surgi-l amount. et a lesser vthickness of the plas c nurture to the softened, exposed margins,ofi` ,the ,bottoni sheet, tiuningv over said sottenedniarginal'parts with the plas-- ,ticv'inixture I. thereon,` upon `the marginal parts ofthe top sheet so as yto overlap and d e'rejss. the same, ott smoothing out the .afa-ves or undulatjioi'is in the thus far linished` product, and of. finally adhering the said top'aidbottom .sheets to the plastic 1.00%#`I K The Icontinuous process of making plas- .ter' bpard, which y.consists of advancingr a .lapttoin sheet offibrous materialfand softening, the marginall parts thereof, of deposit- ,ing a. plastic niiiXture `on said bottom sheet togit'orin thebody oftheboarehin such man'- Aner as to leave softened marginal parts bare and exposed, of su'perposing` a narrower to sheetofiibrous material on saidr` plastic .mixture ,andsat t'liesame -ti1. n .e spreadingthe mixture' evenly .over' thegbottom'sheet tothe .'.desiied thickness', in. flowing upon the,` exposed softenedniarginal parts during the ,spreading yof the plastic mixture, a small amount of .saidV mixture, Aof turning over said softened .part-s With the plastic mixture .thereom .'.upon the marginal parts o fI the -top'sheet so as to overlap' and depress. the saine, of smoothing out the Waves or'fundulations inthe board and of tinallyadhering, the. said top y and bottom S'hftst@ thllS-i 'b0d5--v y l 4;. .Thecontinueus recess of making plas.- -terfbearftWiehl-Genesis .0f advancing a ,'vslieetvot .siaedrpaper and in softening;l thein tlier '1naro-inal parts thereof, of .ijlepositingi plasticrinixture onV said bottom vlsheet t o f o n .the body ofA the.board',l between itssoftd@ illusies; ,which left barze am .expose s'iiperposing;al narrower top I on i the plastic i niizgtuneon the .botti-i131.. .Slifeetandfat- .th .saine-time .ewmg a Small ameuatefplastc 'mixture-uren fh@ softened,4 eiipose L'margins of the lbottoni :Sheet andus reading theplastie mixture y Q??Ft. ,et-Pei@ l0f the-bttoiiishet be.- t Ii said gsoftenedrinargins, 'of' t urning erensa1't-.S9ite-1isdl margins: with. the small amounted. plastic. mixture thereo n, .A one to' the wetswi- :Persbtfhe .toa .Sheetfse'sioioverlap andY depress the samer. ,of,. i r. oning product, to thoroughly adhere the said top and bottom sheets of paper to the plastic body.

5. The continuous process of making plaster board, which comprises advancing a b ottom sheet of fibrous material, superposing thereon plastic material to form the body ofk the board, confining said plasticmaterial in such a manner on said bottom sheet as to leave marginal parts of said sheet eX- posed at each side of t-he same beyond the intended width of the plaster board, superposing a narrower top sheet of fibrousmaterial on said plastic mix and spreading the plastic Inix evenly over the bottom sheet to the intended thickness of the board, turning over the projecting marginal parts of the bottom sheet upon the marginal parts ofthe top sheet, first spreading on Said projecting parts a quantity of plaster so that said plas` ter is turned over with the said projecting marginal parts of the bottom sheet upon vthe marginal parts ofl the top sheet, the turning-over process being continued so yas to `depress the marginal parts of the top sheet.

6. The method of making plasterboard which comprises, depositing plastic material upon a bottom cover sheet, spreading said plast-ic material uniformly upon said bottom sheet, placing a cover sheet upon` said plastic material, folding` the margins of the bottom sheet over the margins of the top sheet, but first weakening the stiffness of said margins so as to fold more readily, and then cementing said folded margins in place. l

7. The method of making plaster board which comprises, depositing plastic material upon a ybottom cover sheet, spreading said plastic material uniformly upon said bottom sheet, placing a cover sheet upon said plastic material, treating the margins of said lower sheet so as to fold more readily, folding said margins over the margins of the top sheet and securing the same in place.

8. A method of making plaster board or the like which comprises depositing plast-ic material on a continuously moving cover sheet, confining saidplastic materialA to a width less than t-he width of said sheet,plac

ing a narrow top sheet on said plastic material and spreadlng the latter over the first sheet tothe intended thickness of the board,l

lap the margins of the top sheet and adher ing the same thereto by means of the plastic material on said margins. n

.10. The methodof making a covered edge plaster' board which is characterized by assembling continuously travelling cover sheets with a mass of plaster between and applying pressure to the assembled elements to cause the plaster to spread unobstructed to anfeven depth throughout the intended width of the board, and then folding cover sheet margins over the plaster at the edge of the board to provide a covered edge` board,

thereby avoiding any obstruction to the latveral flow of the plaster.

' 11. Themethod of making a covered edge plaster board by the vcontinuous process which is characterized by deferring the folding of the cover sheet'margins to cover the `edge of the. plaster body of the'board until the plaster hasbeen spread to an even depth i throughout the widthv of the board, thereby `causing the edges of the board to be entirely lilled with plaster unobstructed by any folded cover sheet margins.

12. Ap'method of making plaster board which is characterized by assembling top and bottom cover sheets with an intervening body of plaster, applying pressure toA cause y the plaster to spread to an veven depth throughout the intended width of the board .and causing a quantity of` plaster to spread upon the cover sheet margins, and then `folding said margins with the plaster thereon uponthe opposite face of the board and ap-v plying'pressure tosaid margins whereby the plaster thereon depresses the underlying margins and provides aspace for a substan tial layer of plaster between the overlapping cover sheet margins. z

MORGAN ARMSTRONG. 

